Resorcinol as a highly efficient aromatic electron donor in bioelectrochemical system

Area of Science:

• Environmental Science
• Biotechnology
• Electrochemistry

Background:

• Bioelectrochemical systems (BESs) show promise for degrading aromatic contaminants and recovering energy.
• Current research primarily focuses on aromatics metabolized via the benzoyl-CoA pathway, with limited studies on other metabolic routes.
• Resorcinol, a central intermediate in anaerobic biodegradation distinct from benzoyl-CoA, represents an understudied area in BES applications.

Purpose of the Study:

• To investigate the degradation of resorcinol, a non-benzoyl-CoA pathway aromatic contaminant, in BESs.
• To evaluate the energy recovery efficiency and performance of BESs when fed with resorcinol.
• To elucidate the microbial mechanisms involved in resorcinol degradation and current generation within BESs.

Main Methods:

• Utilized BESs with resorcinol as the primary substrate.
• Measured current density and coulombic efficiency to assess performance.
• Analyzed microbial communities in the biofilm using advanced techniques.
• Conducted additional experiments with acetate removal to explore degradation pathways.

Main Results:

• Achieved high efficiencies in resorcinol degradation, with current density up to 0.26 ± 0.05 mAcm⁻² and coulombic efficiency of 74.3 ± 10.7%.
• Observed a potential correlation between resorcinol's readily fermentable nature and the high performance.
• Identified syntrophic interactions between resorcinol-degrading bacteria (RDB) and anode-respiring bacteria (ARB) in current generation.
• Evidence suggests direct resorcinol utilization for current generation may also occur.

Conclusions:

• Aromatic contaminants metabolized through the resorcinol pathway can be efficiently treated in BESs with significant energy recovery.
• The findings expand the understanding of aromatic compound fate in BESs, particularly for those not following the benzoyl-CoA pathway.
• BESs offer a viable technology for bioremediation and energy harvesting from a broader range of aromatic pollutants.